Building knowledge across transnational boundaries: Collaboration and friendship in research

•Friendship has contributed to our production of knowledge, how we have created a “relational space”, and worked to maintain our friendship.•Friendship influences our knowledge production process through providing trust and sense of security.•Spending years at the same place has created a space that bonds us, through our experiences of being mothers, students, and co-workers.•Chit-chatting and casual touch-base relations are important to maintain the connection.•Mutual support has elevated individual performances, and simultaneously strengthened our friendship.